The present invention relates to a cooling arrangement of a vehicle for cooling several media in sequence.
Particularly in heavy vehicles there is an increasing need for various forms of cooling. The coolant of the cooling system which cools the combustion engine is increasingly being used to cool also other components of the vehicle, e.g. retarders. Supercharged combustion engines with ever higher charging are being used increasingly to power heavy vehicles for environmental reasons and in response to demands for higher performance. The compressed air needs effective cooling in a charge air cooler before it is led to the combustion engine. For environmental reasons, there is also increasing use of the technique called EGR (Exhaust Gas Recirculation) whereby part of the exhaust gases from a combustion engine is recirculated and mixed with the inlet air to the combustion engine. Adding exhaust gases to the inlet air leads to a lower combustion temperature resulting inter alia in the exhaust gases having a reduced content of nitrogen oxides NOx. The recirculating exhaust gases are cooled in at least one EGR cooler before they are mixed with the air and led to the combustion engine.
Vehicles usually comprise at a front portion an air passage with a radiator fan which provides a forced flow of air through the passage. A radiator for cooling the coolant which cools the combustion engine is usually arranged in such an air passage. In vehicles powered by a supercharged combustion engine, an air-cooled charge air cooler is usually also situated in such an air passage at a position in front of the radiator with the coolant. Such positioning of the charge air cooler makes it possible to cool the charge air to a temperature substantially corresponding to the temperature of the surrounding air. A disadvantage of such positioning is that the coolant undergoes less cooling in the radiator situated to the rear, since it is cooled by air which has already been used for cooling the charge air. However, space in a vehicle is very limited, so it is often necessary to use the existing flow of air in the air passage to cool two or more media in a plurality of cooling elements situated one after another. Any air-cooled EGR cooler used for cooling the recirculating exhaust gases may also be situated in the existing air passage.